Sen. Lamar Alexander, R-Tenn., said the GOP will employ a little-used law that permits the Senate to reject some federal agency regulations by majority vote and denies opponents the ability to thwart action through a filibuster.

Alexander said that by shortening the time between a union’s request for representation and the actual balloting, the NLRB had cleared the way for a new type of “ambush election” to take place that will disadvantage businesses and workers alike.

In remarks on the Senate floor, he said that under previous rules, 95 percent of union elections take place in 56 days or less from the filing of a petition. He said that under the new proposal, that would be reduced to as few as 11 days, which he said could be before an employer understands what’s happening.

In a written statement, NLRB chairman Mark G. Pearce countered that “both businesses and workers deserve a process that is effective, fair, and free of unnecessary delays, which is exactly what this rule strives to accomplish.”

Mirroring divisions in Congress, NLRB rule-making is often politically charged, with Republicans taking the side of business while Democrats are aligned with unions. In the case of the rule approved in December, the labor board split 3-2 along party lines.

The rule, which has been cheered by organized labor, eliminates a previous 25-day waiting period and seeks to reduce litigation that can be used to stall elections. It also requires employers to furnish union organizers with email addresses and phone numbers of workers.

The NLRB rule is scheduled to take effect in April.

Alexander’s announcement was fresh evidence of the Republicans’ determination to use the power won in last fall’s elections, when they captured a Senate majority and strengthened their grip on the House. Obama has already threatened to veto 11 bills.

Alexander said the vote to overturn the union election rule would take place under the Congressional Review Act, which limits debate and bars any changes in the repeal proposal. Obama may veto the measure, however, and it takes the customary two-thirds vote in each house of Congress to override him.

The law being used to target the labor rule has been used successfully only once. That was in 2001, when President George W. Bush signed legislation passed by a Republican-controlled Congress, canceling an ergonomics rule that had been issued by the Labor Department near the end of the Clinton administration.